# Using YAML for inter-process communication - anything built-in? **URL:** \ **Category:** Ruby\ **Created:** [March 2, 2009, 1:15pm UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783 "2009-03-02T13:15:48Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 2, 2009, 1:15pm UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783/1 "2009-03-02T13:15:48Z")
Hi, I’m just wondering - I implemented something ([thbar (Thibaut Barrère) · GitHub](http://github.com/thbar/) petite-lettre/tree/master) I believe probably already exists, can anyone tell me if it does ? I’m using YAML to communicate using stdin/stdout between a Ruby MRI process and a JRuby process (I will soon use it to communicate between IronRuby and JRuby). The parent process launches the child using: PetiteLettre.call(“ruby child\_program.rb”, { :command =\> :start\_sale, :isbn =\> “1234567”, :price =\> 12.4 }) and the child responds with: PetiteLettre.receive do |message| response = {} if message[:command] == :start\_sale # do something here raise “Price is too low” if message[:price] \< 15.0 response[:status] = “OK” response[:transaction\_id] = “1235” else raise “Unknown command ‘#{message[:command]}’” end response end If something already exists in Ruby to do that this way, I’d like to know about it. Any idea ? Thibaut ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 2, 2009, 1:50pm UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783/2 "2009-03-02T13:50:30Z")
On 02.03.2009 13:14, Thibaut Barrère wrote: > The parent process launches the child using: > raise “Price is too low” if message[:price] \< 15.0 > > Any idea ? I am not sure about portability of Marshal across Ruby implementations. In case it is given you could achieve similar results using DRb. Kind regards robert ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 2, 2009, 3:10pm UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783/3 "2009-03-02T15:10:53Z")
Hi Robert, > I am not sure about portability of Marshal across Ruby implementations. > In case it is given you could achieve similar results using DRb. that’s a good point. I’ll try that if I stick with two ruby parties. – Thibaut ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 2, 2009, 10:35pm UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783/4 "2009-03-02T22:35:20Z")
Thibaut Barrère wrote: > If something already exists in Ruby to do that this way, I’d like to > know about it. I came across a YAML-RPC once upon a time; you could try looking for it. I’d avoid YAML as much as possible, as it’s horribly broken; certainly useless for mere humans writing YAML anyway. irb(main):001:0\> require “yaml” =\> true irb(main):002:0\> YAML.load(“foo:bar\nbaz:”) =\> “foo:bar baz:” irb(main):003:0\> YAML.load(“foo:bar\nbaz:\n”) =\> {“foo:bar baz”=\>nil} irb(main):004:0\> YAML.load(“foo:bar\nbaz:bap\n”) =\> “foo:bar baz:bap” irb(main):005:0\> YAML.load(“foo: bar\nbaz:bap\n”) ArgumentError: syntax error on line 2, col -1: `' from /usr/local/lib/ruby/1.8/yaml.rb:133:in`load’ from /usr/local/lib/ruby/1.8/yaml.rb:133:in `load’ from (irb):5 irb(main):006:0\> YAML.load(“foo: bar\nbaz: bap\n”) =\> {“baz”=\>“bap”, “foo”=\>“bar”} There are also examples which have been posted to this list showing objects serialised to YAML and immediately back again, ending up with different content. But I sympathise if you want to do something DRb-like, but between two different Ruby implementations. XMLRPC/JSON won’t give you full Ruby object serialisation, and SOAP is too horrible to contemplate. ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 3, 2009, 10:19am UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783/5 "2009-03-03T10:19:56Z")
Gary Y. wrote: > You’re missing the ‘—’ header in these examples. YAML may behave > more robustly with the header. Nope, it’s exactly the same: irb(main):001:0\> require “yaml” =\> true irb(main):002:0\> YAML.load(“—\nfoo:bar\nbaz:”) =\> “foo:bar baz:” irb(main):003:0\> YAML.load(“—\nfoo:bar\nbaz:\n”) =\> {“foo:bar baz”=\>nil} irb(main):004:0\> YAML.load(“—\nfoo:bar\nbaz:bap\n”) =\> “foo:bar baz:bap” irb(main):005:0\> YAML.load(“—\nfoo: bar\nbaz:bap\n”) ArgumentError: syntax error on line 3, col -1: `' from /usr/lib/ruby/1.8/yaml.rb:133:in `load’ from /usr/lib/ruby/1.8/yaml.rb:133:in `load’ from (irb):5 irb(main):006:0\> YAML.load(“—\nfoo: bar\nbaz: bap\n”) =\> {“baz”=\>“bap”, “foo”=\>“bar”} > Check out FastYAML on github. It’s way faster than YAML, doesn’t use > Syck, and is way more robust than YAML. But is apparently not available as a gem. $ gem sources \*\*\* CURRENT SOURCES \*\*\* [http://gems.rubyforge.org/](http://gems.rubyforge.org/) [http://gems.github.com/](http://gems.github.com/) $ sudo gem search --remote YAML \*\*\* REMOTE GEMS \*\*\* feedtools-cache-yaml (0.0.2) kakutani-yaml\_waml (0.3.0) markbates-yamler (0.1.0) RbYAML (0.2.0) ya2yaml (0.26) yamlconfig (0.1.2) yamler (0.1.0) yamlrpc (1.0.4) yamltest (0.5.1) $ ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 3, 2009, 9:55pm UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783/6 "2009-03-03T21:55:46Z")
Hi Brian, Gary, yeah I’m only simple YAML, and it seems to work for me for what I’m doing. I’ll definitely try to have a C# or Java client consume these and see what happens. Thanks for FastYAML too, interesting. cheers! – Thibaut ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 3, 2009, 12:20am UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783/7 "2009-03-03T00:20:56Z")
You’re missing the ‘—’ header in these examples. YAML may behave more robustly with the header. Check out FastYAML on github. It’s way faster than YAML, doesn’t use Syck, and is way more robust than YAML. -Gary ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 3, 2009, 10:47pm UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783/8 "2009-03-03T22:47:03Z")
Thibaut Barrère wrote: > Hi Brian, Gary, > > yeah I’m only simple YAML, and it seems to work for me for what I’m > doing. I’ll definitely try to have a C# or Java client consume these > and see what happens. > > Thanks for FastYAML too, interesting. One other thought: if it’s simple, look at JSON. It’s easy to extend to serialise arbitrary Ruby objects. YAML can do things like handling multiple references to the same object, but it sounds like you don’t need that level of sophistication. ---
**Author:** ![thbar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/eb8c5e/32.png) [@thbar](https://www.ruby-forum.com/u/thbar)\ **Post date:** [March 4, 2009, 10:30am UTC](https://www.ruby-forum.com/t/using-yaml-for-inter-process-communication-anything-built-in/161783/9 "2009-03-04T10:30:38Z")
> One other thought: if it’s simple, look at JSON. It’s easy to extend to > serialise arbitrary Ruby objects. I’ve been thinking about that. One point that made me choose YAML instead is that YAML support is built-in in STD ruby, where JSON is not (AFAIK). As well from my experience YAML is better covered than JSON on other platforms (such as .Net)… That’s why I choosed YAML for the moment. > YAML can do things like handling multiple references to the same object, > but it sounds like you don’t need that level of sophistication. I don’t need this for the moment, but it may come 🙂 cheers and thanks for the feedback, appreciated – Thibaut